I used a simple circular motion and pushed the gun not pulled. Do you think I should up the heat through the voltage switch (set on number four from six) or up the wire speed a little? I preferred not to increase the wire speed as I was afraid it would leave me with too proud a bead..
up the voltage and maybe knock the wire speed down a touch, this will sink the weld in better and allow you to take more time to concentrate on the front of the puddle to make sure it is melting the root of the weld
On your first run don't weave or go in a circular motion. Aim for a straight push.
Then if you want to build it up and make it stronger you can add more welds, either by more straight runs (for the optimum strength) or by weaving from side to side.